MELBOURNE: Australian thoroughbred Black Caviar, considered the fastest horse in the world, left for Britain Wednesday to race at Royal Ascot with her trainer warning she has never been in better shape.

The champion mare will attempt to win her 22nd race from as many starts in the 1,200-metre Diamond Jubilee Stakes on June 23 and Melbourne-based trainer Peter Moody was supremely confident she will keep her unbeaten record intact.

"She's getting on the plane the fittest she's been in her career," he told reporters.

The horse is the odds-on favourite in antepost betting for the Ascot race.

Moody has gone to extraordinary lengths in his efforts to have Black Caviar ready when she lines up, including providing her with a compression suit to wear on the flight.

Unlike regular passengers, Black Caviar will have to stand in her crate for at least 30 hours, depending on the length of stopovers in Singapore and Sharjah.

Moody said he would consider running her in the 1,200-metre July Cup at Newmarket next month if she came through the Ascot race in good order.